| Linux kernel & device driver programming |
| [ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] |
1 /* 1
2 * af_can.c - Protocol family CAN core module
3 * (used by different CAN protocol
4 *
5 * Copyright (c) 2002-2007 Volkswagen Group El
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary
9 * modification, are permitted provided that t
10 * are met:
11 * 1. Redistributions of source code must reta
12 * notice, this list of conditions and the
13 * 2. Redistributions in binary form must repr
14 * notice, this list of conditions and the
15 * documentation and/or other materials pro
16 * 3. Neither the name of Volkswagen nor the n
17 * may be used to endorse or promote produc
18 * without specific prior written permissio
19 *
20 * Alternatively, provided that this notice is
21 * software may be distributed under the terms
22 * Public License ("GPL") version 2, in which
23 * GPL apply INSTEAD OF those given above.
24 *
25 * The provided data structures and external i
26 * are not restricted to be used by modules wi
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTI
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCH
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIR
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGE
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, S
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE PO
39 * DAMAGE.
40 *
41 * Send feedback to <socketcan-users@lists.ber
42 *
43 */
44
45 #include <linux/module.h>
46 #include <linux/init.h>
47 #include <linux/kmod.h>
48 #include <linux/slab.h>
49 #include <linux/list.h>
50 #include <linux/spinlock.h>
51 #include <linux/rcupdate.h>
52 #include <linux/uaccess.h>
53 #include <linux/net.h>
54 #include <linux/netdevice.h>
55 #include <linux/socket.h>
56 #include <linux/if_ether.h>
57 #include <linux/if_arp.h>
58 #include <linux/skbuff.h>
59 #include <linux/can.h>
60 #include <linux/can/core.h>
61 #include <net/net_namespace.h>
62 #include <net/sock.h>
63
64 #include "af_can.h"
65
66 static __initdata const char banner[] = KERN_I
67 "can: controller area network core ("
68
69 MODULE_DESCRIPTION("Controller Area Network PF
70 MODULE_LICENSE("Dual BSD/GPL");
71 MODULE_AUTHOR("Urs Thuermann <urs.thuermann@vo
72 "Oliver Hartkopp <oliver.hartkop
73
74 MODULE_ALIAS_NETPROTO(PF_CAN);
75
76 static int stats_timer __read_mostly = 1;
77 module_param(stats_timer, int, S_IRUGO);
78 MODULE_PARM_DESC(stats_timer, "enable timer fo
79
80 HLIST_HEAD(can_rx_dev_list);
81 static struct dev_rcv_lists can_rx_alldev_list
82 static DEFINE_SPINLOCK(can_rcvlists_lock);
83
84 static struct kmem_cache *rcv_cache __read_mos
85
86 /* table of registered CAN protocols */
87 static struct can_proto *proto_tab[CAN_NPROTO]
88 static DEFINE_SPINLOCK(proto_tab_lock);
89
90 struct timer_list can_stattimer; /* timer fo
91 struct s_stats can_stats; /* packet s
92 struct s_pstats can_pstats; /* receive
93
94 /*
95 * af_can socket functions
96 */
97
98 static int can_ioctl(struct socket *sock, unsi
99 {
100 struct sock *sk = sock->sk;
101
102 switch (cmd) {
103
104 case SIOCGSTAMP:
105 return sock_get_timestamp(sk,
106
107 default:
108 return -ENOIOCTLCMD;
109 }
110 }
111
112 static void can_sock_destruct(struct sock *sk)
113 {
114 skb_queue_purge(&sk->sk_receive_queue)
115 }
116
117 static int can_create(struct net *net, struct
118 {
119 struct sock *sk;
120 struct can_proto *cp;
121 int err = 0;
122
123 sock->state = SS_UNCONNECTED;
124
125 if (protocol < 0 || protocol >= CAN_NP
126 return -EINVAL;
127
128 if (net != &init_net)
129 return -EAFNOSUPPORT;
130
131 #ifdef CONFIG_KMOD
132 /* try to load protocol module, when C
133 if (!proto_tab[protocol]) {
134 err = request_module("can-prot
135
136 /*
137 * In case of error we only pr
138 * return the error code immed
139 * return -EPROTONOSUPPORT
140 */
141 if (err && printk_ratelimit())
142 printk(KERN_ERR "can:
143 "(can-proto-%d)
144 }
145 #endif
146
147 spin_lock(&proto_tab_lock);
148 cp = proto_tab[protocol];
149 if (cp && !try_module_get(cp->prot->ow
150 cp = NULL;
151 spin_unlock(&proto_tab_lock);
152
153 /* check for available protocol and co
154
155 if (!cp)
156 return -EPROTONOSUPPORT;
157
158 if (cp->type != sock->type) {
159 err = -EPROTONOSUPPORT;
160 goto errout;
161 }
162
163 if (cp->capability >= 0 && !capable(cp
164 err = -EPERM;
165 goto errout;
166 }
167
168 sock->ops = cp->ops;
169
170 sk = sk_alloc(net, PF_CAN, GFP_KERNEL,
171 if (!sk) {
172 err = -ENOMEM;
173 goto errout;
174 }
175
176 sock_init_data(sock, sk);
177 sk->sk_destruct = can_sock_destruct;
178
179 if (sk->sk_prot->init)
180 err = sk->sk_prot->init(sk);
181
182 if (err) {
183 /* release sk on errors */
184 sock_orphan(sk);
185 sock_put(sk);
186 }
187
188 errout:
189 module_put(cp->prot->owner);
190 return err;
191 }
192
193 /*
194 * af_can tx path
195 */
196
197 /**
198 * can_send - transmit a CAN frame (optional w
199 * @skb: pointer to socket buffer with CAN fra
200 * @loop: loopback for listeners on local CAN
201 *
202 * Return:
203 * 0 on success
204 * -ENETDOWN when the selected interface is d
205 * -ENOBUFS on full driver queue (see net_xmi
206 * -ENOMEM when local loopback failed at call
207 * -EPERM when trying to send on a non-CAN in
208 */
209 int can_send(struct sk_buff *skb, int loop)
210 {
211 int err;
212
213 if (skb->dev->type != ARPHRD_CAN) {
214 kfree_skb(skb);
215 return -EPERM;
216 }
217
218 if (!(skb->dev->flags & IFF_UP)) {
219 kfree_skb(skb);
220 return -ENETDOWN;
221 }
222
223 skb->protocol = htons(ETH_P_CAN);
224 skb_reset_network_header(skb);
225 skb_reset_transport_header(skb);
226
227 if (loop) {
228 /* local loopback of sent CAN
229
230 /* indication for the CAN driv
231 skb->pkt_type = PACKET_LOOPBAC
232
233 /*
234 * The reference to the origin
235 * by the receiving socket to
236 * its own. Example: can_raw s
237 * Therefore we have to ensure
238 * reference to the originatin
239 * after each skb_clone() or s
240 */
241
242 if (!(skb->dev->flags & IFF_EC
243 /*
244 * If the interface is
245 * itself, we do it he
246 */
247 struct sk_buff *newskb
248
249 if (!newskb) {
250 kfree_skb(skb)
251 return -ENOMEM
252 }
253
254 newskb->sk = skb->sk;
255 newskb->ip_summed = CH
256 newskb->pkt_type = PAC
257 netif_rx(newskb);
258 }
259 } else {
260 /* indication for the CAN driv
261 skb->pkt_type = PACKET_HOST;
262 }
263
264 /* send to netdevice */
265 err = dev_queue_xmit(skb);
266 if (err > 0)
267 err = net_xmit_errno(err);
268
269 /* update statistics */
270 can_stats.tx_frames++;
271 can_stats.tx_frames_delta++;
272
273 return err;
274 }
275 EXPORT_SYMBOL(can_send);
276
277 /*
278 * af_can rx path
279 */
280
281 static struct dev_rcv_lists *find_dev_rcv_list
282 {
283 struct dev_rcv_lists *d = NULL;
284 struct hlist_node *n;
285
286 /*
287 * find receive list for this device
288 *
289 * The hlist_for_each_entry*() macros
290 * using the pointer variable n and se
291 * struct in each list iteration. The
292 * iteration, d is unmodified when the
293 * points to last list element, when t
294 * but no match in the loop body is fo
295 * NULL when no match is found. We ca
296 * cursor variable n to decide if a ma
297 */
298
299 hlist_for_each_entry_rcu(d, n, &can_rx
300 if (d->dev == dev)
301 break;
302 }
303
304 return n ? d : NULL;
305 }
306
307 static struct hlist_head *find_rcv_list(canid_
308 struct
309 {
310 canid_t inv = *can_id & CAN_INV_FILTER
311
312 /* filter error frames */
313 if (*mask & CAN_ERR_FLAG) {
314 /* clear CAN_ERR_FLAG in list
315 *mask &= CAN_ERR_MASK;
316 return &d->rx[RX_ERR];
317 }
318
319 /* ensure valid values in can_mask */
320 if (*mask & CAN_EFF_FLAG)
321 *mask &= (CAN_EFF_MASK | CAN_E
322 else
323 *mask &= (CAN_SFF_MASK | CAN_R
324
325 /* reduce condition testing at receive
326 *can_id &= *mask;
327
328 /* inverse can_id/can_mask filter */
329 if (inv)
330 return &d->rx[RX_INV];
331
332 /* mask == 0 => no condition testing a
333 if (!(*mask))
334 return &d->rx[RX_ALL];
335
336 /* use extra filterset for the subscri
337 if (*can_id & CAN_EFF_FLAG) {
338 if (*mask == (CAN_EFF_MASK | C
339 /* RFC: a use-case for
340 return &d->rx[RX_EFF];
341 }
342 } else {
343 if (*mask == CAN_SFF_MASK)
344 return &d->rx_sff[*can
345 }
346
347 /* default: filter via can_id/can_mask
348 return &d->rx[RX_FIL];
349 }
350
351 /**
352 * can_rx_register - subscribe CAN frames from
353 * @dev: pointer to netdevice (NULL => subcrib
354 * @can_id: CAN identifier (see description)
355 * @mask: CAN mask (see description)
356 * @func: callback function on filter match
357 * @data: returned parameter for callback func
358 * @ident: string for calling module indentifi
359 *
360 * Description:
361 * Invokes the callback function with the rec
362 * parameter 'data' on a matching receive fil
363 *
364 * <received_can_id> & mask == can_id
365 *
366 * The filter can be inverted (CAN_INV_FILTER
367 * filter for error frames (CAN_ERR_FLAG bit
368 *
369 * Return:
370 * 0 on success
371 * -ENOMEM on missing cache mem to create sub
372 * -ENODEV unknown device
373 */
374 int can_rx_register(struct net_device *dev, ca
375 void (*func)(struct sk_buf
376 char *ident)
377 {
378 struct receiver *r;
379 struct hlist_head *rl;
380 struct dev_rcv_lists *d;
381 int err = 0;
382
383 /* insert new receiver (dev,canid,mas
384
385 r = kmem_cache_alloc(rcv_cache, GFP_KE
386 if (!r)
387 return -ENOMEM;
388
389 spin_lock(&can_rcvlists_lock);
390
391 d = find_dev_rcv_lists(dev);
392 if (d) {
393 rl = find_rcv_list(&can_id, &m
394
395 r->can_id = can_id;
396 r->mask = mask;
397 r->matches = 0;
398 r->func = func;
399 r->data = data;
400 r->ident = ident;
401
402 hlist_add_head_rcu(&r->list, r
403 d->entries++;
404
405 can_pstats.rcv_entries++;
406 if (can_pstats.rcv_entries_max
407 can_pstats.rcv_entries
408 } else {
409 kmem_cache_free(rcv_cache, r);
410 err = -ENODEV;
411 }
412
413 spin_unlock(&can_rcvlists_lock);
414
415 return err;
416 }
417 EXPORT_SYMBOL(can_rx_register);
418
419 /*
420 * can_rx_delete_device - rcu callback for dev
421 */
422 static void can_rx_delete_device(struct rcu_he
423 {
424 struct dev_rcv_lists *d = container_of
425
426 kfree(d);
427 }
428
429 /*
430 * can_rx_delete_receiver - rcu callback for s
431 */
432 static void can_rx_delete_receiver(struct rcu_
433 {
434 struct receiver *r = container_of(rp,
435
436 kmem_cache_free(rcv_cache, r);
437 }
438
439 /**
440 * can_rx_unregister - unsubscribe CAN frames
441 * @dev: pointer to netdevice (NULL => unsubcr
442 * @can_id: CAN identifier
443 * @mask: CAN mask
444 * @func: callback function on filter match
445 * @data: returned parameter for callback func
446 *
447 * Description:
448 * Removes subscription entry depending on gi
449 */
450 void can_rx_unregister(struct net_device *dev,
451 void (*func)(struct sk_
452 {
453 struct receiver *r = NULL;
454 struct hlist_head *rl;
455 struct hlist_node *next;
456 struct dev_rcv_lists *d;
457
458 spin_lock(&can_rcvlists_lock);
459
460 d = find_dev_rcv_lists(dev);
461 if (!d) {
462 printk(KERN_ERR "BUG: receive
463 "dev %s, id %03X, mask
464 DNAME(dev), can_id, mas
465 goto out;
466 }
467
468 rl = find_rcv_list(&can_id, &mask, d);
469
470 /*
471 * Search the receiver list for the it
472 * exist, since no receiver may be unr
473 * been registered before.
474 */
475
476 hlist_for_each_entry_rcu(r, next, rl,
477 if (r->can_id == can_id && r->
478 && r->func == func && r->d
479 break;
480 }
481
482 /*
483 * Check for bugs in CAN protocol impl
484 * If no matching list item was found,
485 * will be NULL, while r will point to
486 */
487
488 if (!next) {
489 printk(KERN_ERR "BUG: receive
490 "dev %s, id %03X, mask
491 DNAME(dev), can_id, mas
492 r = NULL;
493 d = NULL;
494 goto out;
495 }
496
497 hlist_del_rcu(&r->list);
498 d->entries--;
499
500 if (can_pstats.rcv_entries > 0)
501 can_pstats.rcv_entries--;
502
503 /* remove device structure requested b
504 if (d->remove_on_zero_entries && !d->e
505 hlist_del_rcu(&d->list);
506 else
507 d = NULL;
508
509 out:
510 spin_unlock(&can_rcvlists_lock);
511
512 /* schedule the receiver item for dele
513 if (r)
514 call_rcu(&r->rcu, can_rx_delet
515
516 /* schedule the device structure for d
517 if (d)
518 call_rcu(&d->rcu, can_rx_delet
519 }
520 EXPORT_SYMBOL(can_rx_unregister);
521
522 static inline void deliver(struct sk_buff *skb
523 {
524 struct sk_buff *clone = skb_clone(skb,
525
526 if (clone) {
527 clone->sk = skb->sk;
528 r->func(clone, r->data);
529 r->matches++;
530 }
531 }
532
533 static int can_rcv_filter(struct dev_rcv_lists
534 {
535 struct receiver *r;
536 struct hlist_node *n;
537 int matches = 0;
538 struct can_frame *cf = (struct can_fra
539 canid_t can_id = cf->can_id;
540
541 if (d->entries == 0)
542 return 0;
543
544 if (can_id & CAN_ERR_FLAG) {
545 /* check for error frame entri
546 hlist_for_each_entry_rcu(r, n,
547 if (can_id & r->mask)
548 deliver(skb, r
549 matches++;
550 }
551 }
552 return matches;
553 }
554
555 /* check for unfiltered entries */
556 hlist_for_each_entry_rcu(r, n, &d->rx[
557 deliver(skb, r);
558 matches++;
559 }
560
561 /* check for can_id/mask entries */
562 hlist_for_each_entry_rcu(r, n, &d->rx[
563 if ((can_id & r->mask) == r->c
564 deliver(skb, r);
565 matches++;
566 }
567 }
568
569 /* check for inverted can_id/mask entr
570 hlist_for_each_entry_rcu(r, n, &d->rx[
571 if ((can_id & r->mask) != r->c
572 deliver(skb, r);
573 matches++;
574 }
575 }
576
577 /* check CAN_ID specific entries */
578 if (can_id & CAN_EFF_FLAG) {
579 hlist_for_each_entry_rcu(r, n,
580 if (r->can_id == can_i
581 deliver(skb, r
582 matches++;
583 }
584 }
585 } else {
586 can_id &= CAN_SFF_MASK;
587 hlist_for_each_entry_rcu(r, n,
588 deliver(skb, r);
589 matches++;
590 }
591 }
592
593 return matches;
594 }
595
596 static int can_rcv(struct sk_buff *skb, struct
597 struct packet_type *pt, str
598 {
599 struct dev_rcv_lists *d;
600 int matches;
601
602 if (dev->type != ARPHRD_CAN || dev->nd
603 kfree_skb(skb);
604 return 0;
605 }
606
607 /* update statistics */
608 can_stats.rx_frames++;
609 can_stats.rx_frames_delta++;
610
611 rcu_read_lock();
612
613 /* deliver the packet to sockets liste
614 matches = can_rcv_filter(&can_rx_allde
615
616 /* find receive list for this device *
617 d = find_dev_rcv_lists(dev);
618 if (d)
619 matches += can_rcv_filter(d, s
620
621 rcu_read_unlock();
622
623 /* free the skbuff allocated by the ne
624 kfree_skb(skb);
625
626 if (matches > 0) {
627 can_stats.matches++;
628 can_stats.matches_delta++;
629 }
630
631 return 0;
632 }
633
634 /*
635 * af_can protocol functions
636 */
637
638 /**
639 * can_proto_register - register CAN transport
640 * @cp: pointer to CAN protocol structure
641 *
642 * Return:
643 * 0 on success
644 * -EINVAL invalid (out of range) protocol nu
645 * -EBUSY protocol already in use
646 * -ENOBUF if proto_register() fails
647 */
648 int can_proto_register(struct can_proto *cp)
649 {
650 int proto = cp->protocol;
651 int err = 0;
652
653 if (proto < 0 || proto >= CAN_NPROTO)
654 printk(KERN_ERR "can: protocol
655 proto);
656 return -EINVAL;
657 }
658
659 err = proto_register(cp->prot, 0);
660 if (err < 0)
661 return err;
662
663 spin_lock(&proto_tab_lock);
664 if (proto_tab[proto]) {
665 printk(KERN_ERR "can: protocol
666 proto);
667 err = -EBUSY;
668 } else {
669 proto_tab[proto] = cp;
670
671 /* use generic ioctl function
672 if (!cp->ops->ioctl)
673 cp->ops->ioctl = can_i
674 }
675 spin_unlock(&proto_tab_lock);
676
677 if (err < 0)
678 proto_unregister(cp->prot);
679
680 return err;
681 }
682 EXPORT_SYMBOL(can_proto_register);
683
684 /**
685 * can_proto_unregister - unregister CAN trans
686 * @cp: pointer to CAN protocol structure
687 */
688 void can_proto_unregister(struct can_proto *cp
689 {
690 int proto = cp->protocol;
691
692 spin_lock(&proto_tab_lock);
693 if (!proto_tab[proto]) {
694 printk(KERN_ERR "BUG: can: pro
695 proto);
696 }
697 proto_tab[proto] = NULL;
698 spin_unlock(&proto_tab_lock);
699
700 proto_unregister(cp->prot);
701 }
702 EXPORT_SYMBOL(can_proto_unregister);
703
704 /*
705 * af_can notifier to create/remove CAN netdev
706 */
707 static int can_notifier(struct notifier_block
708 void *data)
709 {
710 struct net_device *dev = (struct net_d
711 struct dev_rcv_lists *d;
712
713 if (dev->nd_net != &init_net)
714 return NOTIFY_DONE;
715
716 if (dev->type != ARPHRD_CAN)
717 return NOTIFY_DONE;
718
719 switch (msg) {
720
721 case NETDEV_REGISTER:
722
723 /*
724 * create new dev_rcv_lists fo
725 *
726 * N.B. zeroing the struct is
727 * for the embedded hlist_head
728 * Another list type, e.g. lis
729 * explicit initialization.
730 */
731
732 d = kzalloc(sizeof(*d), GFP_KE
733 if (!d) {
734 printk(KERN_ERR
735 "can: allocatio
736 return NOTIFY_DONE;
737 }
738 d->dev = dev;
739
740 spin_lock(&can_rcvlists_lock);
741 hlist_add_head_rcu(&d->list, &
742 spin_unlock(&can_rcvlists_lock
743
744 break;
745
746 case NETDEV_UNREGISTER:
747 spin_lock(&can_rcvlists_lock);
748
749 d = find_dev_rcv_lists(dev);
750 if (d) {
751 if (d->entries) {
752 d->remove_on_z
753 d = NULL;
754 } else
755 hlist_del_rcu(
756 } else
757 printk(KERN_ERR "can:
758 "found for dev
759
760 spin_unlock(&can_rcvlists_lock
761
762 if (d)
763 call_rcu(&d->rcu, can_
764
765 break;
766 }
767
768 return NOTIFY_DONE;
769 }
770
771 /*
772 * af_can module init/exit functions
773 */
774
775 static struct packet_type can_packet __read_mo
776 .type = __constant_htons(ETH_P_CAN),
777 .dev = NULL,
778 .func = can_rcv,
779 };
780
781 static struct net_proto_family can_family_ops
782 .family = PF_CAN,
783 .create = can_create,
784 .owner = THIS_MODULE,
785 };
786
787 /* notifier block for netdevice event */
788 static struct notifier_block can_netdev_notifi
789 .notifier_call = can_notifier,
790 };
791
792 static __init int can_init(void)
793 {
794 printk(banner);
795
796 rcv_cache = kmem_cache_create("can_rec
797 0, 0, NU
798 if (!rcv_cache)
799 return -ENOMEM;
800
801 /*
802 * Insert can_rx_alldev_list for recep
803 * This struct is zero initialized whi
804 * embedded hlist heads, the dev point
805 */
806
807 spin_lock(&can_rcvlists_lock);
808 hlist_add_head_rcu(&can_rx_alldev_list
809 spin_unlock(&can_rcvlists_lock);
810
811 if (stats_timer) {
812 /* the statistics are updated
813 setup_timer(&can_stattimer, ca
814 mod_timer(&can_stattimer, roun
815 } else
816 can_stattimer.function = NULL;
817
818 can_init_proc();
819
820 /* protocol register */
821 sock_register(&can_family_ops);
822 register_netdevice_notifier(&can_netde
823 dev_add_pack(&can_packet);
824
825 return 0;
826 }
827
828 static __exit void can_exit(void)
829 {
830 struct dev_rcv_lists *d;
831 struct hlist_node *n, *next;
832
833 if (stats_timer)
834 del_timer(&can_stattimer);
835
836 can_remove_proc();
837
838 /* protocol unregister */
839 dev_remove_pack(&can_packet);
840 unregister_netdevice_notifier(&can_net
841 sock_unregister(PF_CAN);
842
843 /* remove can_rx_dev_list */
844 spin_lock(&can_rcvlists_lock);
845 hlist_del(&can_rx_alldev_list.list);
846 hlist_for_each_entry_safe(d, n, next,
847 hlist_del(&d->list);
848 kfree(d);
849 }
850 spin_unlock(&can_rcvlists_lock);
851
852 kmem_cache_destroy(rcv_cache);
853 }
854
855 module_init(can_init);
856 module_exit(can_exit);
857
| This page was automatically generated by the LXR engine. |